Every day tons of paper packaging materials are thrown away. Since the product appears to be made of paper, the end consumer wrongly assumes that the material will quickly degrade which may encourage them to litter, or may even expect the material to be recyclable and place the material in a recycling bin. However, where a paper material has been made waterproof this is commonly by fusing paper with polyethylene, a material that cannot be separated out again in a standard recycling process, and which prevents the material quickly degrading when littered.
This is a particular problem for coffee cups, which are used to sell take-away beverages such as coffee and tea from high-street shops such as coffee shops. These cups are typically made from card which has been treated to be waterproofed and may be provided with a separate or integrated sleeve to insulate the contents and protect the consumers' hands from hot or cold beverage liquids.
It is also known to provide plastic packaging materials and containers, including plastic coffee cups. The use of such polymer materials have many benefits and can provide strong, chemically and biologically inert materials at relatively low cost. Unfortunately many of these characteristics make them difficult to dispose of without causing lasting damage to the environment. The very short functional life of plastic containers leads to rapid build-up of waste material which is inert to most physical and chemical action to which they are subjected during conventional disposal.
As the global population becomes more aware of the human effect on our climate, our ecosystems and the planet as a whole, there is growing demand to increase the amount of waste which is recycled. Accordingly, there is a growing demand for alternatives to conventional polymer materials.
Several degradable polymer compositions have been developed. However, there are significant disadvantages associated with these conventional degradable polymers. Conventional degradable polymers (such as aliphatic polyesters) are generally more difficult and complicated to process, resulting in lower output. These materials have significantly higher densities and lower strength than conventional non-degradable commodity polymers.
U.S. Pat. No. 4,016,117 discloses the use of biodegradable filler materials, such as starch, and an autoxidising substance such as a fat which, when exposed to transition metals in soil, yield peroxides which attack carbon-carbon linkages in the resin.
U.S. Pat. No. 4,931,488 discloses the addition of a biologically degradable substance (starch), an iron compound (FeOH(stearate)2), and a fatty acid or fatty acid ester (such as soya oil which is a mix of fatty acid esters) to a thermoplastic polymer. The resultant plastic composition degrades under the action of heat and/or ultraviolet light and/or insolation. These compositions have disadvantageous abiotic degradation and biodegradation rates.
The modern consumer is becoming increasingly aware of their social responsibilities and their carbon footprint. Accordingly there is increased adverse publicity associated with this waste issue and an environmentally friendly alternative is urgently being sought. Accordingly, it is desirable to provide a degradable sheet material suitable for use in forming packaging or containers, especially coffee cups and/or tackle at least some of the problems associated with the prior art or, at least, to provide a commercially useful alternative thereto. In particular, there is a desire to provide a packaging material or wrapping which is recyclable and in addition, especially if littered, is readily degradable.